<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .parent{
            width:400px;
            background: green;
            /*overflow:hidden;*/
        }
        .child{
            width:200px;
            height: 200px;
            background: red;
            float:left;

        }
        .two{
            width: 400px;
            height: 400px;
            background: blue;
        }
        .row:after{
            content: "";
            display: table;
            clear:both;
        }
        
    </style>
</head>
<body>
    <div class="parent">
        <div class="child"></div>
        <div class="row"></div>
    
    </div>
  <div class="two"></div>
  
</body>
</html>
